PSEUDOSTOMA BOREALIS.---RICH. MSS.
[Thomomys bulbivorus]
THE CAMAS RAT.
[Camas Pocket Gopher]
PLATE CXLII.---MALE, FEMALE, and YOUNG.
P. Ex cinereo fulvus, cauda longa pilosa; P. bursario minor, et gracilior,
dentibus unguibusque minoribus.
CHARACTERS.
Smaller and of more delicate form than Pseudostoma bursarius, and teeth and
claws much smaller. Tail, long, and clothed with hair. Colour, pale
yellowish-gray.
SYNONYMES.
GEOMYS BOREALIS. Rich., MSS.
PSEUDOSTOMA BOREALIS. Bach., Jour. Acad. Nat. Sciences Philadelphia,
vol. vii, part 1, p. 103.
GEOMYS TOWNSENDII. Rich., MSS.
DESCRIPTION.
Head, of moderate size; ears, consisting of a small round opening margined
by an elevated ridge, the highest portion of which is the posterior part, and is
about one line in height. The ears not hidden by the fur, but distinctly
visible. Body, moderately thick; claws of the fore-feet, slender and rather
long; incisors, rather long (but not large for the genus); the upper ones have
each a slight longitudinal groove situated close to the inner margin. Tip of
nose, naked; feet, bare beneath; inner toe of fore-feet, rather short, outer
next in length, middle longest, and the toes on either side of the central one
about equal; there is a long brush of stiff white hairs on the inner side of the
inner toe. On the hind-feet the central toe is longest, outer toes equal and
short. Tail, hairy.
COLOUR.
General colour, pale gray, the upper parts more or less washed with yellow;
inside of pouches, under surface of body, feet, and tail, white. Hairs of the
body, dark slate colour at the roots. There is a dusky spot behind the ears;
incisors, yellow; claws, white; tail, above, grayish, tinged with yellow.
DIMENSIONS.
Inches. Lines.
From nose to root of tail,. . . . . . 7 6
Tail,. . . . . . . . . . . . . 2 0
Tarsus and claws,. . . . . . . . . 1 1 1/2
Central claw of fore-foot,. . . . . . 0 5
Nose to ear, . . . . . . . . . . 1 6 1/2
The above description was made from three specimens of this pouched
Sand-rat, obtained by the late Mr. TOWNSEND, on the Columbia river, two of which
appeared to be in summer pelage, and the third in its autumnal coat.
Description of another specimen sent by Mr. TOWNSEND, marked in RICHARDSON's
MSS. as Geomys Townsendii:
Form and size of the animal, nearly the same as in the specimens just
described, with the exception of the tail, which is considerably longer.
General colour, very pale gray above, with a faint yellowish wash; end of nose,
dusky gray; under parts, grayish-white; chin, pure white; tail and feet, white,
the former grayish above. Hairs of the back, very pale gray at the roots, pale
yellow near the tips, the extreme points cinereous. Teeth, yellowish-white;
upper incisors, with a faint groove near the internal margin. Claws and
fore-feet, moderate white.
DIMENSIONS.
Inches. Lines.
From nose to tail, . . . . . . . . 7 6
Tail,. . . . . . . . . . . . . 2 9
Tarsus, . . . . . . . . . . . . 1 3 1/2
Central claw of fore-foot,. . . . . . 0 5
Nose to ear, . . . . . . . . . . 1 5
HABITS.
The Camas Rat derives its name, according to RICHARDSON, from its fondness
for the bulbous root of the quamash or camas plant (Scilla esculenta).
Like all the pouched Rats of America, it feeds upon nuts, roots, seeds, and
grasses, and makes burrows, extending long distances, but not very far beneath
the surface of the ground, throwing up mole-hills in places as it comes to the
surface. These animals are generally found to be in a certain degree
gregarious, or at least a good many of them inhabiting the same locality, and
more or less associated together; and are said to be very common on the plains
of the Multnomah river.
Mr. DOUGLAS informed Sir JOHN RICHARDSON that they may be easily snared in
the summer.
We believe that some of the Indians of those parts of Oregon in which this
burrowing Rat exists eat them, but have no information concerning the
peculiarities they exhibit, the number of young they produce at a time, or the
depredations they commit on the fields and gardens of the settlers.
In the Fauna Boreali Americana (p. 206), this pouched Rat (if we are not
mistaken), is given as Diplostoma bulbivorum--Camas Rat--and under the
impression that that name applies to our present animal, we have made the above
remarks in relation to it.
GEOGRAPHICAL DISTRIBUTION.
Specimens were obtained both by DOUGLAS and DRUMMOND, about the same period
of time, in the vicinity of the Columbia river in Oregon.
GENERAL REMARKS.
On a visit to Europe we carried with us three specimens of pouched
Sand-Rats, which we regarded as belonging to the same species, but being male,
female, and young. Our object was to compare them with specimens taken from
this country at the north and west by RICHARDSON, DOUGLAS, DRUMMOND, and other
naturalists. RICHARDSON kindly showed us a specimen brought from the Columbia
river by DOUGLAS, which, as we thought, appeared to be of the same species as
our own. As he was then preparing a monograph of this perplexing genus, we
requested him to describe the species, and add it to his monograph; he
consequently gave it the above name. He however called another specimen which
we had carried with us, Geomys Townsendii. We think his monograph was never
published.
We have united what he considered two species--Geomys Borealis and G.
Townsendii--into one, having added the latter as a synonyme; and we have
rejected Diplostoma as a genus, not only because we conceive the characters on
which it is founded to be the result of an unnatural disposition of the pouches
in the dried skins, but for the reason mentioned above viz., that we consider
the so-called Diplostoma bulbivorum to be identical with the animal we have just
described as Pseudostoma borealis, although the description given by RICHARDSON
has apparently no reference to the latter, but on the contrary describes his
Diplostoma as having the true mouth vertical (?). He says: "The lips, which in
fact are right and left, and not upper and under," &c. Besides, in the
beginning of his article he mentions that the skull is wanting. We think we may
therefore reasonably presume, that although the skin had been so twisted and
disfigured by putting it into an unnatural form that the appellation which Mr.
DOUGLAS gave it, as "the animal known on the banks of the Columbia by the name
of the Camas Rat," did not seem to apply to it, we shall be right in rejecting
both the generic and specific names given by our friend Sir JOHN RICHARDSON to
so very imperfect a specimen, and in believing that the skin was in reality
(although much injured and distorted) nothing but the Camas Rat, as DOUGLAS
called it.